| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2005, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| */ |
| package com.ibm.icu.text; |
| import com.ibm.icu.impl.Utility; |
| import com.ibm.icu.impl.UtilityExtensions; |
| import java.util.Vector; |
| |
| /** |
| * A transliterator that is composed of two or more other |
| * transliterator objects linked together. For example, if one |
| * transliterator transliterates from script A to script B, and |
| * another transliterates from script B to script C, the two may be |
| * combined to form a new transliterator from A to C. |
| * |
| * <p>Composed transliterators may not behave as expected. For |
| * example, inverses may not combine to form the identity |
| * transliterator. See the class documentation for {@link |
| * Transliterator} for details. |
| * |
| * <p>Copyright © IBM Corporation 1999. All rights reserved. |
| * |
| * @author Alan Liu |
| * @internal |
| */ |
| class CompoundTransliterator extends Transliterator { |
| |
| private Transliterator[] trans; |
| |
| private int numAnonymousRBTs = 0; |
| |
| private static final String COPYRIGHT = |
| "\u00A9 IBM Corporation 1999-2001. All rights reserved."; |
| |
| /** |
| * Constructs a new compound transliterator given an array of |
| * transliterators. The array of transliterators may be of any |
| * length, including zero or one, however, useful compound |
| * transliterators have at least two components. |
| * @param transliterators array of <code>Transliterator</code> |
| * objects |
| * @param filter the filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| * @internal |
| */ |
| public CompoundTransliterator(Transliterator[] transliterators, |
| UnicodeFilter filter) { |
| super(joinIDs(transliterators), filter); |
| trans = new Transliterator[transliterators.length]; |
| System.arraycopy(transliterators, 0, trans, 0, trans.length); |
| computeMaximumContextLength(); |
| } |
| |
| /** |
| * Constructs a new compound transliterator given an array of |
| * transliterators. The array of transliterators may be of any |
| * length, including zero or one, however, useful compound |
| * transliterators have at least two components. |
| * @param transliterators array of <code>Transliterator</code> |
| * objects |
| * @internal |
| */ |
| public CompoundTransliterator(Transliterator[] transliterators) { |
| this(transliterators, null); |
| } |
| |
| /** |
| * Constructs a new compound transliterator. |
| * @param ID compound ID |
| * @param direction either Transliterator.FORWARD or Transliterator.REVERSE |
| * @param filter a global filter for this compound transliterator |
| * or null |
| * @internal |
| */ |
| public CompoundTransliterator(String ID, int direction, |
| UnicodeFilter filter) { |
| super(ID, filter); |
| init(ID, direction, true); |
| } |
| |
| /** |
| * Constructs a new compound transliterator with no filter. |
| * @param ID compound ID |
| * @param direction either Transliterator.FORWARD or Transliterator.REVERSE |
| * @internal |
| */ |
| public CompoundTransliterator(String ID, int direction) { |
| this(ID, direction, null); |
| } |
| |
| /** |
| * Constructs a new forward compound transliterator with no filter. |
| * @param ID compound ID |
| * @internal |
| */ |
| public CompoundTransliterator(String ID) { |
| this(ID, FORWARD, null); |
| } |
| |
| /** |
| * Package private constructor for Transliterator from a vector of |
| * transliterators. The caller is responsible for fixing up the |
| * ID. |
| */ |
| CompoundTransliterator(Vector list) { |
| this(list, 0); |
| } |
| |
| CompoundTransliterator(Vector list, int numAnonymousRBTs) { |
| super("", null); |
| trans = null; |
| init(list, FORWARD, false); |
| this.numAnonymousRBTs = numAnonymousRBTs; |
| // assume caller will fixup ID |
| } |
| |
| /** |
| * Finish constructing a transliterator: only to be called by |
| * constructors. Before calling init(), set trans and filter to NULL. |
| * @param id the id containing ';'-separated entries |
| * @param direction either FORWARD or REVERSE |
| * @param idSplitPoint the index into id at which the |
| * splitTrans should be inserted, if there is one, or |
| * -1 if there is none. |
| * @param splitTrans a transliterator to be inserted |
| * before the entry at offset idSplitPoint in the id string. May be |
| * NULL to insert no entry. |
| * @param fixReverseID if TRUE, then reconstruct the ID of reverse |
| * entries by calling getID() of component entries. Some constructors |
| * do not require this because they apply a facade ID anyway. |
| */ |
| private void init(String id, |
| int direction, |
| boolean fixReverseID) { |
| // assert(trans == 0); |
| |
| Vector list = new Vector(); |
| UnicodeSet[] compoundFilter = new UnicodeSet[1]; |
| StringBuffer regenID = new StringBuffer(); |
| if (!TransliteratorIDParser.parseCompoundID(id, direction, |
| regenID, list, compoundFilter)) { |
| throw new IllegalArgumentException("Invalid ID " + id); |
| } |
| |
| TransliteratorIDParser.instantiateList(list); |
| |
| init(list, direction, fixReverseID); |
| |
| if (compoundFilter[0] != null) { |
| setFilter(compoundFilter[0]); |
| } |
| } |
| |
| /** |
| * Finish constructing a transliterator: only to be called by |
| * constructors. Before calling init(), set trans and filter to NULL. |
| * @param list a vector of transliterator objects to be adopted. It |
| * should NOT be empty. The list should be in declared order. That |
| * is, it should be in the FORWARD order; if direction is REVERSE then |
| * the list order will be reversed. |
| * @param direction either FORWARD or REVERSE |
| * @param fixReverseID if TRUE, then reconstruct the ID of reverse |
| * entries by calling getID() of component entries. Some constructors |
| * do not require this because they apply a facade ID anyway. |
| */ |
| private void init(Vector list, |
| int direction, |
| boolean fixReverseID) { |
| // assert(trans == 0); |
| |
| // Allocate array |
| int count = list.size(); |
| trans = new Transliterator[count]; |
| |
| // Move the transliterators from the vector into an array. |
| // Reverse the order if necessary. |
| int i; |
| for (i=0; i<count; ++i) { |
| int j = (direction == FORWARD) ? i : count - 1 - i; |
| trans[i] = (Transliterator) list.elementAt(j); |
| } |
| |
| // If the direction is UTRANS_REVERSE then we may need to fix the |
| // ID. |
| if (direction == REVERSE && fixReverseID) { |
| StringBuffer newID = new StringBuffer(); |
| for (i=0; i<count; ++i) { |
| if (i > 0) { |
| newID.append(ID_DELIM); |
| } |
| newID.append(trans[i].getID()); |
| } |
| setID(newID.toString()); |
| } |
| |
| computeMaximumContextLength(); |
| } |
| |
| /** |
| * Return the IDs of the given list of transliterators, concatenated |
| * with ';' delimiting them. Equivalent to the perlish expression |
| * join(';', map($_.getID(), transliterators). |
| */ |
| private static String joinIDs(Transliterator[] transliterators) { |
| StringBuffer id = new StringBuffer(); |
| for (int i=0; i<transliterators.length; ++i) { |
| if (i > 0) { |
| id.append(';'); |
| } |
| id.append(transliterators[i].getID()); |
| } |
| return id.toString(); |
| } |
| |
| /** |
| * Returns the number of transliterators in this chain. |
| * @return number of transliterators in this chain. |
| * @internal |
| */ |
| public int getCount() { |
| return trans.length; |
| } |
| |
| /** |
| * Returns the transliterator at the given index in this chain. |
| * @param index index into chain, from 0 to <code>getCount() - 1</code> |
| * @return transliterator at the given index |
| * @internal |
| */ |
| public Transliterator getTransliterator(int index) { |
| return trans[index]; |
| } |
| |
| /** |
| * Append c to buf, unless buf is empty or buf already ends in c. |
| */ |
| private static void _smartAppend(StringBuffer buf, char c) { |
| if (buf.length() != 0 && |
| buf.charAt(buf.length() - 1) != c) { |
| buf.append(c); |
| } |
| } |
| |
| /** |
| * Override Transliterator: |
| * Create a rule string that can be passed to createFromRules() |
| * to recreate this transliterator. |
| * @param escapeUnprintable if TRUE then convert unprintable |
| * character to their hex escape representations, \\uxxxx or |
| * \\Uxxxxxxxx. Unprintable characters are those other than |
| * U+000A, U+0020..U+007E. |
| * @return the rule string |
| * @internal |
| */ |
| public String toRules(boolean escapeUnprintable) { |
| // We do NOT call toRules() on our component transliterators, in |
| // general. If we have several rule-based transliterators, this |
| // yields a concatenation of the rules -- not what we want. We do |
| // handle compound RBT transliterators specially -- those for which |
| // compoundRBTIndex >= 0. For the transliterator at compoundRBTIndex, |
| // we do call toRules() recursively. |
| StringBuffer rulesSource = new StringBuffer(); |
| if (numAnonymousRBTs >= 1 && getFilter() != null) { |
| // If we are a compound RBT and if we have a global |
| // filter, then emit it at the top. |
| rulesSource.append("::").append(getFilter().toPattern(escapeUnprintable)).append(ID_DELIM); |
| } |
| for (int i=0; i<trans.length; ++i) { |
| String rule; |
| |
| // Anonymous RuleBasedTransliterators (inline rules and |
| // ::BEGIN/::END blocks) are given IDs that begin with |
| // "%Pass": use toRules() to write all the rules to the output |
| // (and insert "::Null;" if we have two in a row) |
| if (trans[i].getID().startsWith("%Pass")) { |
| rule = trans[i].toRules(escapeUnprintable); |
| if (numAnonymousRBTs > 1 && i > 0 && trans[i - 1].getID().startsWith("%Pass")) |
| rule = "::Null;" + rule; |
| |
| // we also use toRules() on CompoundTransliterators (which we |
| // check for by looking for a semicolon in the ID)-- this gets |
| // the list of their child transliterators output in the right |
| // format |
| } else if (trans[i].getID().indexOf(';') >= 0) { |
| rule = trans[i].toRules(escapeUnprintable); |
| |
| // for everything else, use baseToRules() |
| } else { |
| rule = trans[i].baseToRules(escapeUnprintable); |
| } |
| _smartAppend(rulesSource, '\n'); |
| rulesSource.append(rule); |
| _smartAppend(rulesSource, ID_DELIM); |
| } |
| return rulesSource.toString(); |
| } |
| |
| /** |
| * Return the set of all characters that may be modified by this |
| * Transliterator, ignoring the effect of our filter. |
| * @internal |
| */ |
| protected UnicodeSet handleGetSourceSet() { |
| UnicodeSet set = new UnicodeSet(); |
| for (int i=0; i<trans.length; ++i) { |
| set.addAll(trans[i].getSourceSet()); |
| // Take the example of Hiragana-Latin. This is really |
| // Hiragana-Katakana; Katakana-Latin. The source set of |
| // these two is roughly [:Hiragana:] and [:Katakana:]. |
| // But the source set for the entire transliterator is |
| // actually [:Hiragana:] ONLY -- that is, the first |
| // non-empty source set. |
| |
| // This is a heuristic, and not 100% reliable. |
| if (!set.isEmpty()) { |
| break; |
| } |
| } |
| return set; |
| } |
| |
| /** |
| * Returns the set of all characters that may be generated as |
| * replacement text by this transliterator. |
| * @internal |
| */ |
| public UnicodeSet getTargetSet() { |
| UnicodeSet set = new UnicodeSet(); |
| for (int i=0; i<trans.length; ++i) { |
| // This is a heuristic, and not 100% reliable. |
| set.addAll(trans[i].getTargetSet()); |
| } |
| return set; |
| } |
| |
| /** |
| * Implements {@link Transliterator#handleTransliterate}. |
| * @internal |
| */ |
| protected void handleTransliterate(Replaceable text, |
| Position index, boolean incremental) { |
| /* Call each transliterator with the same start value and |
| * initial cursor index, but with the limit index as modified |
| * by preceding transliterators. The cursor index must be |
| * reset for each transliterator to give each a chance to |
| * transliterate the text. The initial cursor index is known |
| * to still point to the same place after each transliterator |
| * is called because each transliterator will not change the |
| * text between start and the initial value of cursor. |
| * |
| * IMPORTANT: After the first transliterator, each subsequent |
| * transliterator only gets to transliterate text committed by |
| * preceding transliterators; that is, the cursor (output |
| * value) of transliterator i becomes the limit (input value) |
| * of transliterator i+1. Finally, the overall limit is fixed |
| * up before we return. |
| * |
| * Assumptions we make here: |
| * (1) contextStart <= start <= limit <= contextLimit <= text.length() |
| * (2) start <= start' <= limit' ;cursor doesn't move back |
| * (3) start <= limit' ;text before cursor unchanged |
| * - start' is the value of start after calling handleKT |
| * - limit' is the value of limit after calling handleKT |
| */ |
| |
| /** |
| * Example: 3 transliterators. This example illustrates the |
| * mechanics we need to implement. C, S, and L are the contextStart, |
| * start, and limit. gl is the globalLimit. contextLimit is |
| * equal to limit throughout. |
| * |
| * 1. h-u, changes hex to Unicode |
| * |
| * 4 7 a d 0 4 7 a |
| * abc/u0061/u => abca/u |
| * C S L C S L gl=f->a |
| * |
| * 2. upup, changes "x" to "XX" |
| * |
| * 4 7 a 4 7 a |
| * abca/u => abcAA/u |
| * C SL C S |
| * L gl=a->b |
| * 3. u-h, changes Unicode to hex |
| * |
| * 4 7 a 4 7 a d 0 3 |
| * abcAA/u => abc/u0041/u0041/u |
| * C S L C S |
| * L gl=b->15 |
| * 4. return |
| * |
| * 4 7 a d 0 3 |
| * abc/u0041/u0041/u |
| * C S L |
| */ |
| |
| if (trans.length < 1) { |
| index.start = index.limit; |
| return; // Short circuit for empty compound transliterators |
| } |
| |
| // compoundLimit is the limit value for the entire compound |
| // operation. We overwrite index.limit with the previous |
| // index.start. After each transliteration, we update |
| // compoundLimit for insertions or deletions that have happened. |
| int compoundLimit = index.limit; |
| |
| // compoundStart is the start for the entire compound |
| // operation. |
| int compoundStart = index.start; |
| |
| int delta = 0; // delta in length |
| |
| StringBuffer log = null; |
| if (DEBUG) { |
| log = new StringBuffer("CompoundTransliterator{" + getID() + |
| (incremental ? "}i: IN=" : "}: IN=")); |
| UtilityExtensions.formatInput(log, text, index); |
| System.out.println(Utility.escape(log.toString())); |
| } |
| |
| // Give each transliterator a crack at the run of characters. |
| // See comments at the top of the method for more detail. |
| for (int i=0; i<trans.length; ++i) { |
| index.start = compoundStart; // Reset start |
| int limit = index.limit; |
| |
| if (index.start == index.limit) { |
| // Short circuit for empty range |
| if (DEBUG) { |
| System.out.println("CompoundTransliterator[" + i + |
| ".." + (trans.length-1) + |
| (incremental ? "]i: " : "]: ") + |
| UtilityExtensions.formatInput(text, index) + |
| " (NOTHING TO DO)"); |
| } |
| break; |
| } |
| |
| if (DEBUG) { |
| log.setLength(0); |
| log.append("CompoundTransliterator[" + i + "=" + |
| trans[i].getID() + |
| (incremental ? "]i: " : "]: ")); |
| UtilityExtensions.formatInput(log, text, index); |
| } |
| |
| trans[i].filteredTransliterate(text, index, incremental); |
| |
| // In a properly written transliterator, start == limit after |
| // handleTransliterate() returns when incremental is false. |
| // Catch cases where the subclass doesn't do this, and throw |
| // an exception. (Just pinning start to limit is a bad idea, |
| // because what's probably happening is that the subclass |
| // isn't transliterating all the way to the end, and it should |
| // in non-incremental mode.) |
| if (!incremental && index.start != index.limit) { |
| throw new RuntimeException("ERROR: Incomplete non-incremental transliteration by " + trans[i].getID()); |
| } |
| |
| if (DEBUG) { |
| log.append(" => "); |
| UtilityExtensions.formatInput(log, text, index); |
| System.out.println(Utility.escape(log.toString())); |
| } |
| |
| // Cumulative delta for insertions/deletions |
| delta += index.limit - limit; |
| |
| if (incremental) { |
| // In the incremental case, only allow subsequent |
| // transliterators to modify what has already been |
| // completely processed by prior transliterators. In the |
| // non-incrmental case, allow each transliterator to |
| // process the entire text. |
| index.limit = index.start; |
| } |
| } |
| |
| compoundLimit += delta; |
| |
| // Start is good where it is -- where the last transliterator left |
| // it. Limit needs to be put back where it was, modulo |
| // adjustments for deletions/insertions. |
| index.limit = compoundLimit; |
| |
| if (DEBUG) { |
| log.setLength(0); |
| log.append("CompoundTransliterator{" + getID() + |
| (incremental ? "}i: OUT=" : "}: OUT=")); |
| UtilityExtensions.formatInput(log, text, index); |
| System.out.println(Utility.escape(log.toString())); |
| } |
| } |
| |
| /** |
| * Compute and set the length of the longest context required by this transliterator. |
| * This is <em>preceding</em> context. |
| */ |
| private void computeMaximumContextLength() { |
| int max = 0; |
| for (int i=0; i<trans.length; ++i) { |
| int len = trans[i].getMaximumContextLength(); |
| if (len > max) { |
| max = len; |
| } |
| } |
| setMaximumContextLength(max); |
| } |
| } |